California Grass Tribes (Bluegrass, Oat, Brome, Melic, Wheat, Needlegrass, Reed, Lovegrass, Bermuda Grass, Summary Key)
By Bruce Homer-Smith

Summary Key

Tribe	Infl Branched	Awns	Glumes	Special Characteristics
Bluegrass	Y	YN	Short, membranous	Infl may be contracted. Small spikelets. Leaf collar hairy.
Oat	Y	YN	Long, papery	Infl may be contracted. Awns from floret back, not the tip.
Brome	Y	Mostly	Short. Florets visible.	Infl may be contracted. Spikelets widen, then taper.
Melic	YN	Mostly not	Short, papery. Florets visible.	Leaf sheath closed. Florets cylindrical, not flattened, papery edges.
Wheat	N	YN	Short.	Spikelets in two ranks and press into stem.
Needle Grass	Y	Mostly	Long, membranous	Bunch Grass. Awns to 9”. Floret cylindrical, not flat, rigid.
Reed	Y	Mostly not	Long, covers the florets	Tall, plume inflorescences except Oatgrass. Silky hairs.
Lovegrass	Many times	YN	Short	Small spikelets, hairy leaf sheaths, glands on both.
Bermuda Grass	YN	N	Short.	Rows of small spikelets attach to finger-like branches.

Infl = Inflorescence

Here are the grass tribes you’re most likely to encounter in California:

Bluegrass Tribe (Poeae)

Diagram © Tatiana Sendusky, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

Spikelets are small, with several florets. They’re membranous or leathery. If present (e.g. Festuca), awns are straight and come from the tip of the floret.

Glumes are membranous and shorter than the whole spikelet, so florets show above them

The inflorescence is branched but may be contracted or open. Non-woody stems do not branch before the inflorescence. Leaf collars are not hairy.

Common CA genera: Briza (Rattlesnake Grass), Cynosurus (Dogtail Grass), Dactylis (Orchard Grass), Festuca (Fescue), Gastridium, Lamarckia (Golden Top), Poa (Blue Grass), Puccinellia (Alkali Grass), Scribneria.

Exception – Festuca perennis has a spike-like inflorescence.

More on the Bluegrass Tribe.

Oat Tribe (Aveneae)

Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

Spikelets have one to many florets that are flattened. Florets sometimes have awns that come from the back, not the tip. Awns can be straight or bent, as in the diagram.

Long glumes, often papery, usually cover the rest of the spikelet.

The inflorescence is branched but may be contracted or open.

California Genera: Agrostis (Bent Grass), Aira (Hair Grass), Avena (Oats), Calamagrostis (Reed Grass), Holcus (Velvet Grass), Phalaris (Canary Grass), Phleum (Timothy), Trisetum (Oat Grass), Polypogon (Beard Grass), Alopecurus, Ammophila, Anthoxanthum, Arrhenatherum, Beckmannia, Cinna, Hierochloe, Koeleria, Sphenopholis.

More on the Oat Tribe.

Brome Tribe (Bromeae)

Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

Spikelets widen from the base and then taper as florets get smaller at the tip.

Glumes are shorter than the lowest floret, allowing the many florets to show above them.

Florets are flattened and usually have straight or recurved awns, starting near the tip. They’re herbaceous or leathery, not membranous.

The inflorescence is branched but may be contracted or open.

The closed leaf sheath ends in a characteristic V-shaped top.

California Genus: Bromus (Brome).

More on the Brome Tribe.

Melic Tribe (Meliceae)

Coast Range Melic (Melica imperfecta) Photo by Keir Morse

Tall Mannagrass (Glyceria elata) Photo © Neal Kramer

The inflorescence is branched but is so contracted in many Melicas that it looks spike-like.

Spikelets have short, papery glumes, several florets and no awns.

Florets are cylindrical, not flattened. They have papery edges.

Leaf sheaths are closed.

Exception – Awned Melic (M. aristata) has awns.

The only California genus in this tribe is Melica.

More on the Melica Tribe.

Wheat Tribe (Triticeae)

Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Spikelets are flattened, and connect directly to the stem in two ranks. Spikelets press into the stem which is often indented at the spikelet.

Glumes are shorter than the one-to-many florets.

Some leaf blades have ear-like flaps (auricles) where they join the sheath (Hordeum and Elymus)

California Genera: Aegilops, Agropyron, Elymus (Wild Rye), Hordeum (Barley), Leymus, Secal (Rye), Triticum (Wheat)

More on the Wheat Tribe.

Needlegrass Tribe (Stipeae)

Purple Needle Grass (Stipa pulchra)

Drawing © John Muir Laws

These are bunch grasses with narrow, branched inflorescences.

Spikelets have a single cylindrical floret, commonly with an awn from 1/8” to 9” long, sometimes bent.

The floret is membranous to rigid.

Glumes are membranous and long enough to hide the floret.

The primary California genus is Stipa (Needle Grass).

Reed Tribe (Arundineae)

Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

These are tall, reed-like grasses with tall, plume-like inflorescences. Exception: oat grasses are smaller.

Florets are surrounded by silky hairs.

Glumes cover the florets.

California Genera: Arundo (Giant Reed), Cortaderia (Pampas Grass), Danthonia (Oatgrass) and Phragmites (Common Reed).

Lovegrass Tribe (Eragrostideae)

Diagram © Lynn Clark, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

Lovegrass inflorescences are much branched (twice or thrice divided is common) but the branches may be hard to see because they’re short.

Spikelets have 3-to-many, hairless, flattened florets showing over short glumes.

Ligules have hairs on their margin (ciliate), as do the tops of the leaf sheaths.

Leaf sheaths and spikelets have characteristic glands on their surface.

California Genera: Erigrostis (Love Grass), Distichlis (Salt Grass), Eleusine (Goosegrass), Leptochloa (Sprangletop), Muhlenbergia (Muhly), Sporobolus (Dropseed), Tridens.

Bermuda Grass Tribe (Cynodonteae)

Diagram © Tatiana Sendusky, ‘Agnes Chase’s First Book of Grasses’, 4^th edition

Annotations Bruce Homer-Smith

This tribe is easy to pick out, with rows of spikelets attaching on one side of the branch. Spikelets are tiny, each attaching directly to its branch.

Branches are whorled at the top of the stem (digitate) or extend from the main stem.

California Genera: Bouteloua (Gramma), Chloris (Finger Grass), Cynodon (Bermuda Grass), Hilaria (Galleta), Spartina (Cord Grass).

Corrections/Comments: bruce@PlantID.net Copyright: https://PlantID.net/Contributors.aspx